Detergency is defined as the ability to wet, emulsify, suspend, penetrate, and disperse soils. Conventional detergents used in the warewashing and laundering industries include alkaline detergents. Alkaline detergent formulations employing alkali metal carbonates and/or alkali metal hydroxides, intended for both institutional and consumer use, are known to provide effective detergency, particularly when used with phosphorus-containing compounds.
Phosphates are multifunctional components commonly used in detergents to reduce water hardness as well as increase detergency, anti-redeposition, and crystal modification. In particular, polyphosphates such as sodium tripolyphosphate and their salts are used in detergents because of their ability to prevent calcium carbonate precipitation and their ability to disperse and suspend soils. If calcium carbonate is allowed to precipitate, the crystals may attach to the surface being cleaned and cause undesirable effects. For example, calcium carbonate precipitation on the surface of ware can negatively impact the aesthetic appearance of the ware and give the ware an unclean look. In the laundering area, if calcium carbonate precipitates and attaches onto the surface of fabric, the crystals may leave the fabric feeling hard and rough to the touch. In addition to preventing the precipitation of calcium carbonate, the ability of sodium tripolyphosphate to disperse and suspend soils facilitates the detergency of the solution by preventing the soils from redepositing into the wash solution or wash water.
However, the use of phosphorous raw materials in detergents has become undesirable for a variety of reasons, including environmental reasons. Due to recent regulations, work has recently been directed to replacing phosphorus in detergents. There is therefore a need in the art for an environmentally friendly multifunctional component that can replace the properties of phosphorous-containing compounds such as phosphates, phosphonates, phosphites, and acrylic phosphinate polymers.
Enzymes have been employed in cleaning compositions since early in the 20th century. It was not until the mid-1960's when enzymes were commercially available with both the pH stability and soil reactivity for detergent applications. Enzymes are known as effective chemicals for use with detergents and other cleaning agents to break down soils. Enzymes break down soils making them more soluble and enabling surfactants to remove them from a surface to provide enhanced cleaning of a substrate.
Enzymes can provide desirable activity for removal of, for example, protein-based, carbohydrate-based, or triglyceride-based stains from substrates. As a result, enzymes have been used for various cleaning applications in order to digest or degrade soils such as grease, oils (e.g., vegetable oils or animal fat), protein, carbohydrate, or the like. For example, enzymes may be added as a component of a composition for laundry, textiles, ware washing, cleaning-in-place, drains, floors, carpets, medical or dental instruments, meat cutting tools, hard surfaces, personal care, or the like. Although enzyme products have evolved from simple powders containing alkaline protease to more complex granular compositions containing multiple enzymes and still further to liquid compositions containing enzymes, there remains a need for alternative cleaning applications employing stabilized enzymes. Numerous mechanisms for improving stabilization of enzymes for storage in liquid compositions, namely in liquid detergent compositions have been employed, such as disclosed in U.S. Pat. No. 8,227,397, which is incorporated by reference in its entirety. However, there remains a need for improvement such that liquid use compositions retain detergency and cleaning performance when exposed to high temperatures, pH and/or extended periods of time under use conditions.
Accordingly, it is an objective of the invention to develop a solid stabilized detergent composition with a protease enzyme and stabilizing agent such that storage and/or transport of the compositions are not limited. Moreover, such solid compositions are thereafter suitable for generating stabilized use solutions able to retain suitable enzyme stability under elevated temperature and pH conditions of use.
It is a further objective of the invention to develop multi-use, stabilized use solutions of detergent compositions and enzymes to enhance enzyme stability under elevated temperature and pH conditions to provide improved detergency.
It is an objective of the invention to develop methods for use of stabilized enzymes and/or stabilized use solutions containing enzymes for improved detergency.
It is a further objective of the invention to develop methods for use of stabilized enzymes and/or stabilized use solutions to retain enzyme and use solution stability for at least about 20 minutes or greater at temperatures from about 65-80° C. or greater and under alkaline conditions at a pH between about 9 and about 11.5. Beneficially, such objectives overcome significant limitations of the state of the art of enzyme stability in detergent compositions, namely wherein unstabilized enzyme activity significantly decreases over time, including within short time periods of as little as 5-20 minutes.
In an aspect of the invention, the enzymatic activity is retained under elevated temperature and pH conditions by the stabilization of enzyme-containing detergent compositions and/or detergent use solutions.
A further object of the invention is to develop multi-use compositions and methods for employing the same, to improve protein removal and antiredeposition properties of low phosphorus detergents, in particular sodium carbonate based detergents.
These and other objects, advantages and features of the present invention will become apparent from the following specification taken in conjunction with the claims set forth herein.